A puzzle solver finds enjoyment in the challenge of assembling or arranging pieces or filling in blanks to obtain the final form or state of the successfully completed puzzle. The utility of a puzzle primarily lies in the process the puzzle solver must perform to obtain this final form or state and only incidentally in the final form or state resulting when the puzzle is successfully completed. For example, once completed, a crossword puzzle is essentially worthless; similarly, while the pieces of a jigsaw puzzle may be assembled to form an interesting or beautiful picture, jigsaw puzzles are normally disassembled when the assembly process is complete. Accordingly, the process performed is the most important aspect of a successfully designed puzzle and should present a new and interesting challenge to the puzzle solver.
The utility of toys for children generally is derived in large part from the above-mentioned factors describing the utility of a puzzle; in addition, however, a toy should be educational and allow a child to be creative.